Grice extra-articular subtalar fusion for spastic pes planovalgus

Introduction A pes planovalgus deformity, an unstable foot deformity, affects the gait of children with cerebral palsy (CP). Treatments, including subtalar fusion, were proposed. The Grice procedure maintains foot stability, but bone graft non-union poses a challenge. This study aimed to identify the rate and factors related to post-operative bone graft non-union. Methods Thirty-one paediatric CP patients (age, 8.9 +/- 1.8 years) who underwent the Grice procedure (53 feet) using ipsilateral tibial bone grafts were reviewed. Pre-operative gross motor function classification system (GMFCS) classes were class 1 in five, 2 in five, 3 in 14, and 4 in seven patients. Standing foot radiographs were assessed for signs of non-union, and parameters (talocalcaneal and talar declination angles and talar head uncovering index) measured pre-operatively, post-operatively, and at the most recent evaluation were compared. Factors associated with bone graft non-union were analysed by regression analysis. P < 0.05 was considered statistically significant. Degenerative changes in hindfoot joints were evaluated by Bargon's criteria. Results At the average follow-up evaluation at 5.4 +/- 4.3 years, the GMFCS class was improved or was maintained in 29/31 patients. Post-operative radiographic measurements were restored and were maintained over the follow-up period (P < 0.001). A total of 14/53 feet (26%) had non-union. The pre-operative lateral talocalcaneal angle (OR 1.08, p = 0.04) and follow-up duration (OR 1.18, p = 0.03) were identified in univariate analysis as potential factors related to non-union but were not confirmed in a multivariate model. Hindfoot joints in most feet showed mild degenerative changes. Conclusion Grice subtalar fusion in patients with a higher pre-operative lateral talocalcaneal angle might lead to bone graft non-union.